Reddit mentions of Straight Science? Homosexuality, Evolution and Adaptation

Well, there are a few hypotheses on the adaptive advantage of homosexuality. I know the Gay Uncle hypothesis has been mentioned, and that's basically what you described. However, there are competing ideas. The evidence behind the evolutionary explanation for homosexuality is the existence of a genomic complex that has been found in homosexual/bisexual populations. Basically, we know that variation of sexuality exists on a genetic level, which is the foundation for modern evolutionary biology*. Here is a summary of an interesting cross-cultural study about it. There's also the maternal stress/epigenetic idea that is quite known now, too.

​

The book Straight Science? Homosexuality, Evolution, and Adaptation is a bit dated now, but it goes over a lot of crucial ideas in understanding sexuality as a biological/genetic phenomenon. His central argument is a bit different, though. He contends that homosexuality is a genetic hiccup. The homosexual gene complex would exist in heterosexual individuals, and depending on their expression and variation, could offer a type of reproductive advantage**. However, complete homosexuality is a sort of byproduct of this gene expression and variation. Think a simple Punnett Square for this.

​

I'm not keen on overpopulation explanations, and I don't think there's good evidence to support it, either. And it's important to understand that while our biology and genes play a role in sexuality, sexual identity, and whatnot, I don't support a whole genetic determinism (in fact, most biologists don't, either). No doubt environmental (which also includes cultural) pressures are involved here. I just don't like to give way to the complete social construction of sexuality and identity (you can listen to this podcast where a former gay conversion therapist supports the social construction of sexuality and identity for because it kinda supports him).

​

*Important to note that epigenetics is an important part of evolutionary biology, but biologists are unsure how much epigenetics influences natural selection and evolution.

** Unfortunately, most studies done on human homosexuality focus on male homosexuality (and we know female homosexuality is, in some ways, different than male homosexuality). We really do need more studies on female homosexuality.